Thermodynamic pumping apparatus



Dec. 27, 1927.

1,653,719 W..MAUSS THERMODYNAMIG PUMPING APPARATUS Filed June 18, 1926 2S heetsSheet l n ren hr- W. MAUSS THEHMODYNAMIC PUMPING APPARATUS Dec. 27, 1927. I 1,653,719

Filed June 18. 1926 2 Sheets-Sheet 2 Q A A o x H Patented Dec.- 27, 19 27.

UNITED STATES- WILHEL'M MAUSS, OF DURBAN, N'A'IAL, SOUTH AFRICA.

rnnnmonxnnnrc PUMPING nrrnan'ros.

Applicatiomfiled time 18, 1926. Serial No. 116,997

The present invention relates to a method and apparatus for converting the thermal I energy of fuel into mechanical energy.

Oneof the main objects of the invention is-to burn the fuel in an internal combustion apparatus in which the working finid operates according to the Diesel or semi-Dlesel cycle, but to deliver the energy,to a rotating shaft by meansof an engine of the steam in engine type.

The principal feature of the inventlon 1s a thermodynamic transformer whereby the thermal energy of fuel is employed to produce heated compressed air, which may then beused like steam in a suitable engine.

The transformer may be regarded as a two-stroke internal combustion engine in which the. gas charge is worked according to the. Diesel or semi-Diesel cycle to the extent of compressing the air charge, injecting fuel thereto and igniting the gas charge so for-med, expanding the gas charge and thereby driving out the piston, exhausting the gas charge, scavenging and filling the l cylinder-with afresh air charge, and compressing said fresh air charge by the return 'of the piston. In the present case however there is no energy. output during the expansion stroke, the energy developed during i that stroke being stored and returned to.

effect the succeeding inward stroke. Also the piston stroke is considerably prolonged outwardly as compared with that of a Diesel engine, with the result that the fresh air charge taken in for compression is in excess of that required for thenext expansion stroke. The whole of this fresh all charge is at first compressed in the usual way by the inward stroke of the piston, but after V a portion of such stroke has been effected. the excess air, now compressed and heated by compression, is discharged from the cylinder. This constitutes the output of the transformer and as above mentioned, may

be employed as the working fluid ofa suitable engine. The remaining air is further compressed to the proper pressure for Diesel or semi-Diesel working, and, upon being fueled and ignited, constitutes the working 1 so charge for the next outward stroke.

The piston is mechanically free,-its.outward stroke being stopped and itsinward stroke effected by fluid pressure acting continuously to force it inwards. The length a; of the piston stroke is therefore not fixed but varies according to the energy delivered to the piston by the combustion; so that by using substantially constant pressure to. op-

pose and return the piston, the volume of the excess air taken in for compression and discharged in each cycle is automatically proportioned to the energy available for compressing it. The mechanical balance of the apparatus is preserved by using two opposed pistons in the cylinder.

Provision is made for utilizing the discharged compressed air for driving the transformer piston when required, as when starting the transformer or to compensate for mis-fires or the like.

The invention isillustrated in the accompanying drawing in which Fig. I shows a power plant comprising the transformer and the engine; the cylinder of the transformer being in longitudinal section and some parts of the apparatus being indicated diagrammatically,

Fig. II is a vertical cross section on II-II Fig. I. Fig. III is a diagram illustrating the op- -eration of the transformer.

Figs. IV to VII are enlarged views showing details of the various valve mechanisms...

Thetransformer cylinder comprises the barrels 2 and the middle ring 3 which accommodates certain valves and fittings; the barrels and ring forming one continuous cylinder which is suitably supported and jacketed. In the cylinder two pistons 4 are arranged to reciprocate oppositely from the centre point 5.

The outward movement of the pistons is resisted and their-inward movement eifected by pressure of a fluid, conveniently air, on their outer faces. 6 is a low pressure reservoir containing at a pressure which is approximately the means pressure of the gas between the pistons during the working stroke. Said reservoir is directly and constantly connected to the outer ends of the cylinderby pip'es 7 of large area to "avoid friction. Beyond said pipes the cylinder is continued at each. end as a closed cushioning chamber 8 to prevent any possibility of the pistons st-rikingthe cylinder ends.

Oil plungers 9, 9*,project from the pistons 4 into the oil chambers 10,10? Gham her 10 is-connected by a large bore pipe 11 to the chamber of a two-bore governor cylinder 12 in which works the lower face 13 of a differential governor piston 14. Simiillv larly oil chamber is connected by pipe 11 to the cylinder chamber in which works the lower piston face 13.

The piston faces 13, 13 are of equal areas and are collectively equal inarea to the upper face of the piston 14. Low pressure air from the receiver 6 acts, through the pipe 16, on the piston face-15 and thus, through the oil columns, on the faces of the oil plungcrs t), 9. The low pressure air accordingly acts directly and indirectly, on the entire outer face of each of the pistons 4. As the pistons 4 are floating, they would, unless controlled, not necessarily keep symmetrically positioned with regard to the centre point 5. The plun ers 9, 9, the oil columns, and the differential piston 14 constitute a means for ensuring such symmetri cal displacement of the pistons, operating as follows. As the plungers 9, 9 move outwards they displace oil from the chambers 10, 10, which acts on the piston faces 13,

13, to force the governor piston 14 upagainst the air pressure on its face 15. As"

the oil is substantially incompressible, any lag of movement of one piston 4 relative to the other would cause the lagging piston to cease to exert pressure, through its oil column, on its corresponding face of the piston 14 so that the resistance to said pistons movement would disappear, whilst simultaneously the overrunning piston would take, through its plunger face and its oil column, all the load of the air pressure on the piston 14. The lagging piston would accordingly be accelerated by the gas pressure behind it and the overrunnmg piston retarded by the oil pressure; the effect being suificiently instantaneous to maintain the pistons at all times in the r proper relative positions within very small limits. It will be evident that a similar governing action takes place on the inward stroke, the lagging piston in that case taking all the load of the governor piston-14 and theoverrunning piston none of said load.

The area of the plungers 9, 9" in relation to the area of the pistons 4 is adjusted according to the variation of resistance to .the movementof the pistons which has to be provided for. The plunger shown being of one tenth the area of the pistons 4, rovideagainst a difference between the resistances of the pistons (due to friction or to the transformer being tilted endwise) equal to one tenth of theair pressure resistance.

Oil leakage is made up from a source 17 of oil maintained under appropriate pressure. The make-up oil is directed to whichever column requires it by valves 18, 19 actuated by a cam 20. Said cam is attached to the indicating mechanism next described and opens one or other of the valves 18, 19 according to its direction of movement.

Indicating mechanism is provided to keepthe attendant informed as to the symmetrical positioning of the pistons 4. The pistons 4 are prevented from turning by rods 21 which are also utilized to convey cooling liquid to the pistons. In conjunction with each plunger 9, 9, is a rotatable rod 22 formed with one or two turns of a quick screw thread and engaging a similarly threaded nut 23 in the end of the plunger. Reciprocatory movement of the pistons 4, without rotation, causes oscillatory rotation of the rods 22. The rods 22 are severally connected by a gearing 24, 24 to the similar gear wheels 25, 25 of an epicyclic gear, causing said wheels 25 to rotate oppositely to one another. The part upon which the third wheel 26 of the gear rotates is extended and functions as an indicating arm 27. So longas the retations of the wheels 25 are equal, the third wheel 26 rotates only on its own axis; but unequal displacement of the pistons 4, by causing one wheel 25 to rotate more than the other, sets up planetary movement of the third wheel 26, which is shown by the arm 27. The cam 20 for operating the oil valves 18, 19 is fixed to and moves with the arm 27.

Movement of the governor piston 14 is utilized to control the operations of the sev' eral valves associated with the cylinder 2. It is for this purpose provided with two piston rods 28 supporting a panel 29, co-operating with which are a number of valve operating arms mounted on a common sha ft 30. The fuel injection valve 31 is positioned at the centre of the cylinder. It is loaded by a spring 32 and provided with a plunger beneath which the fuel is forced to open the valve. The spring 32 is so adjusted that a fuel pressure of several hundred pounds per square inch above that of the gas in the cylinder, is required to open the valve thus ensuring that the fuel is injected into the cylinder under high pressure which 011-.

sures its thorough atomization. Fuel is supplied by a spring-actuated pump 34 (Fig. IV) the piston of which is raised by a bell crank lever 35 and held by a latch 36. Said latch is tripped to release the pump, at the moment the pistons 4 stop, at their inner position, by a tappet 37 loosely attached to one of the governor piston rods 28 by a spring 38. The pistons 4 come to'rcst somewhat suddenly at the inner end of the stroke owing to the rapid increase of pressure of the air enclosed between them. The governor piston l4 accordingly stops with equal suddenness, the momentum of the tappct 37 thereupon causing it to move on for a short distance, and trip the latch 36. The pump is raised during the outward stroke of the pistons 4 by a block 39 on the panel 29 coming into contact with a rotating double ended lever 40 which acts on a third arm 41 of the bell crank 35.

I This type of pump is employed in preference to the more usual cam type, to give the rapid fuel injection rendered desirable by the rapid starting movement of the pispistons in the cylinder.

tons 4. The length of the stroke of the pump and consequently the amount'of fuel injected, is varied by a sliding wedge 42 operated by a spring controlled piston 43 subjected to the pressure of air in the receiver 44 into which the transformer delivers its product. The arrangement is such that the fuelv supply is gradually cut off as the pressure in the receiver 44 .approaches a desired upper limit. 7

45 is the exhaust valve (detailed in Fig. V) which-is opened when the pistons 4 have moved outwards, and the governor piston 14 has consequently moved upwardly, a pre-,

determined distance. The closing of this valve however coincides with the commencement of the return movement of the pistons 4 and not with any definite position of the The valve mechanism for this I In the push rod 46 is a knuckle joint 51 which is rigid against upward thrust and yields to downward thrust. A block 52 on the panel 29 thrusts out the push rod to open the valve. As the panel 29 commences its return movement, its frictional drag causes the knuckle joint 51 to collapse, so permitting sudden return of the rod 46 and closing of the valve. A light spring'53 keeps the jointed end of the rod in contact with the panel 29.

The air inlet or scavenging valve 54 opens and closes automatically with the exhaust valve. It controls scavenging airsupplied from a source 55 at a pressure of a few pounds above atmospheric pressure. When the exhaust valve 45 opens and the pressure in the cylinder falls to about'atmospheric pressure, the scavenging air presses open the inlet valve and flows into the cylinder, displacing the products of combustion and pro-' viding the fresh air charge in thecylinder. Upon the exhaust valve closing, the pressure on each side of the inlet valve'is equalized, permitting said valve to be closed by its light spring 56.

57 is an air delivery valve situated at the middle of the cylinder. Its function is to pass to the receiver 44 the heated and compressed air which is the product of the transformer. It is loaded by the receiverair and is free to be lifted. and thereby opened when purpose comprises a push rod 46 supported on the the air in the cylinder reaches a pressure slightly greater than the receiver pressure. It is however also capable of being closed, whether lifted or not, by so rotating it that its wings 58-cover the outlet ports 59 in its casing. Its actuating mechanism is shown in Fig. VI and comprises the double-stepped block 60 on the panel 29, the bell crank 61, the link 62 having a lost-motion connection 63 to the bell crank 64, and the link 65 connecting the bell crank 64' to the arm 66 on the valve spindle 67.

On the inward stroke of the pistons 4, when the panel 29 is moving downwardly,

the lower step of the block 60 takes up the slack at 63. Thereafter the upper step of.

the same block operates the entire connection from 61 to 67 and rotates the valve to close the ports 59. During the subsequent outward movement of the pistons 4, the passing of the upper step of block 60 takes up the slack in the opposite direction and the passing of the lower step thereafter allows thespring 68 to restore the entire connection and thus re-open the ports 59. the lost motion this re-opening of the ports Owing to 59 takes place at a stage in the expansion of the working gas when its pressure has fallen sulficiently to have permitted the valve 57 to drop back to its seat. Accordingly no connection between the cylinder and the receiver is made by this valve during the outward stroke.

69 is a valve, also positioned at the middle of .the cylinder, by which under certain circumstances high pressure air from the receiver 44is re-admitted to the cylinder. Details of this valve appear in Fig. VII.

On the spindle of this valve is a piston Cylinder. P

providing the faces 70 and 71. pressure' is applied constantly to the piston face 70 by the connection 72, and the area ofsaid face 70 is equal to the area of the valve face 7 3 exposed to the cylinder. The

connection 74 from the receiver 44 opens. between the upper face 7 5 of the valve and the lower piston face 71 which latter is rather larger than the valve face 75. The

valve is accordingly always substantially,

balanced notwithstanding variations of the cylinder and receiver pressures, but with a preponderance of receiver pressure which tends to holdthe valve to its seat. The valve is depressed and opened by a bell crank 76, having a handle 77 for manually operating it. 7 8 is a bar which is guided for endwise reciprocation by the link 79 and the slotted headSO. It is thus reciprocated towards the right in Figs. II and VII by the block 81 on the panel 29, which, at an early point in the outward stroke of the pistons 4, releases it and permits it to be reciprocated towards the left by the spring 82. Thereafter another block-83 moves it again towards the right. A pr g pawl 849a the ar can engage the left, the valve 69 is ppened and held open for a period to pass air from the receiver 44 to the cylinder 2. If however the cylinder pressure is sufiiciently high at that moment, the valve (39 remains closed.

The receiver 44 is well lagged to conserve the heat of the air passed into it. It need not be of large capacity, since any variation of supply to or,within limits-withdrawal from it is quickly corrected automatically as will be seen hereafter.

From the receiver 44 the heated compressed air is taken' by a pipe 88 to the engine 89, which is shown as a triple expansion reciprocating engine. In said pipe 88 is a balanced valve 90 closed by a spring 91 and opened by receiver pressure on its control piston 92. An abnormal drop of pres sure in. the receiver closes said valve 90 and prevents further withdrawal of air therefrom until the'receiver pressure has been restoredby the delivery of sufficient air from the transformer.

The operation is as follows, reference being made to the diagram of Fig. I-II. Assuming the apparatus to be working normally, and the pistons 4 to he at their innerpositions as shown in Fig. I, a previously formed gas charge between them is ignited and the pistons are driven outwards in opposite directions. Their outward movement is resisted and eventually stopped by the low pressure air acting on their outer faces.

The expansion of the gas during the outward stroke is indicated in Fig. III by the line A, B, G, and it will be observed that by a suitable adfustment of the pressure OH of the low pressure air which resists the outward stroke, the expansion stroke is allowed to proceed considerably farther than that A D of the .usual Diesel or semi-Diesel cycle indicated by A, B, D, E, A.

During the outward stroke the governor piston 13 moves upwards," and at the point C of the stroke, the block 52 opens the exhaust. valve 45. The pressure in the cylinder falls to about atmospheric pressure. and

the inlet valve 54- consequently opens by the pressure of the air behind it, admitting a. scavenging charge of fresh air to the cylinder. Eiiicient scavenging and consequent high volumetric efiiciency result from the exhaust and scavenging valves being at op-.

posite ends of the cylinder space.

After the termination of the gas. expansion at the point C, the outward stroke still continues by the momentum of the pistons 4 to some farther point 1*, at which the energy absorbed by the low pressure air plus the energy lost by friction, equals the energy given out by the expanding gas. At this 'point F the pistons stop and, by the continned pressure of the low pressure air on them, begin their inward stroke.

The consequent reversal of the movement of the pancl'29 causes the knuckle 51 to collapse, so permitting the exhaust valve to close. lhe pressure on both sides of the inlet valve 54 being thereby equalized, said inlet valve closes.

The fresh charge of air thus enclosed between the pistons is now compressed by the continued inward driving of the pistons by the low pressure air. Due to the initial pressure F, F of the air charge and the distance of F from the origin 0, the curve (F G) of compression is higher than the expansion curve A, B, C, and eventually reaches the point G at which the pressure within the cylinder'is slightly above the pressure in the receiver 44. The valve 57 consequently lifts, and continued inward movement of thepistons 4 expels air from the cylinder to the receiver as indicated by the line G, B, E.

Before point E of the stroke has been reached, the lower step of the block 60 has taken up the slack in the connection (33; and upon point E being reached, the upper step of said block 60 operates the connecting mechanisms 61, 62, 64, 65, 66 to rotate the valve spindle 67 and thereby cause the valve wings 58 to close the ports 59.

Expulsion of air from the cylinder is thereby terminated at such a distance of the pistons from the centre point 5 of the cylinder that the final inward movement of the pistons brings the remaining air to the high compression required to form the next gas charge, the compression being indicated by line from E towards A.

It will he noted that although the pistons are floating the steepness of the compression curve at the end of the compression stroke causes the compressed air charge to stop them at a position which does not vary Inaterially. The stoppage of the pistons is abrnpt,.as is that of the governor piston 14.

The momentum of the tappet 37 however causes it'to move on for a further short distance, when it trips the catch 3(3'and permits the fuel pump 34 to be thrust down by its spring. Fuel is thereby injected into the compressed air charge in the cylinder at the proper moment irrespective of the actual stopping positions of the pistons; and the charge being ignited, the next outward stroke is started.

In the diagram the area A, B, E, indi cates heat energy expended, and, G, B, C,

F, F, the energy of the expelled air, their values being equal, subject to friction and heat losses.

The compressed air conveyed tothe receiver 44 is passed to the engine 89 to drive the same. Being at constant pressure and highly heated by the compression, it can be used, in the same way as steam from a boiler, in engines designed to use steam; thus avoiding some of the difficulties of employing Diesel engines, in, for example, ship propulsion.

' The air must of course be exhausted when expanded to about atmospheric pressure; its heat content, as a rule, enabling it to be expanded to this extent without freezing. If desired however further heat can be added to it during the lower expansion stages; the heated acket fluid of the transformer being available for this purpose.

The construction of the transformer renders it to a large extent self governing under various circumstances. If for instance, the pressure of the receiver 44 drops somewhat due to increased Withdrawal of air from it,

the line G, B, E, of the diagram is lowered and the final compression correspondingly rises. More power is developed in the next expansion and the outward stroke is lengthened, spacing the point F in the diagram farther from the origin 0. A larger fresh air charge is accordingly taken in and the excess air delivered in greater volume. In other words, the air charge in each cycle is made proportionate to the energy developed ready for taking up by said charge.

On account of this variation in the stroke length the low pressure is maintained at substantially constant pressure by the provision of a suitably large receiver 6, so that the length of the stroke and the volume of the fresh air charge, however they may vary, maintain a somewhat closely constant ratio to the amount of energy developed in each cycle. The automatic valve 90 is provided to prevent. the pressure in the receiver falling to such a point as would permit the air delivery valve 57 to open unduly early and so cause an excessive accumulation of energy in the cylinder.

If the pressure in the receiver 44 increases, the fuel supply is gradually cut off. The first effect is to shorten the stroke of the pistons 4 and consequently to reduce the air charge. Further. cutting ofl of the fuel causes the expansion line A, B, C, to be below the pressure of the receiver 44- when the bar 78 begins its movement to the left. The lowered position of the plunger 85 due-to the low cylinder pressure will then permit the pawl 84 to engage the bell crank 7 6 and open the air return valve 69. Air at receiveri pressure will then enter the cylinder 2 ,the quantity admitted being sufliclent to ensure the pistons 4 being driven past the exhaust valve 45. The normal cycle then proceeds, air being returned to the'receiver on the inward stroke. When the fuel is entirely shut off and also when a misfire occurs during normal running, the transformer remains in operation in this manner, the amount of air returned to the receiver 44 naturally being less than that Withdrawn therefrom.- To stop the transformer the fuel injection is cut off, and the valve 92 in connection 74 is closed in order to prevent the transformer from being driven by air from the receiver 44.

The transformer is started by building up the low air pressure, whereby the pistons 4 are brought together. The receiver 44 is then charged with air of appropriate high pressure from an auxiliary and the valve 69 is opened first by means of its handle 7 7 and then held open for a periodby the bar 78. The air drives the pistons as described above until ignition occurs; whereupon the plunger 85 rises and further supply of high-pressure air to the cylinder is prevented.

The horizontal arrangement of the cylinder 2 prevents the weight of the pistons 4 having any effect on the cycle. The mass of the pistons has the important function of absorbing, as kinetic energy, the energy delivered by the gas or air on the driving side of the pistons during the first part of either the inward or outward stroke, and giving out such energy to the air on the other side during the later part of the stroke. The mass of the pistons is proportioned to the rate of reciprocation desired, the greater the mass the slower the reciprocation, and vice versa.

The transformer is capable of considerable thermodynamic efficiency due to the long expansion stroke, the straight through scavening and the low jacket losses due to the low average gas temperature throughout the cycle; such low average temperature resulting from the rapid acceleration of the pistons when the gas temperature is high, low terminal ten'iperature and the somewhat slow rate of the return stroke caused by the low pressure air. .The combination of the transformer with the steam type of engine is accordingly capable of a net thermal efficiency which compares favourably with that of a Diesel engine. An important application of the invention is to the conversion of existing steam installations by replacing the boiler plant by transformers as described, the steam engines being retained.

I claim 1. A thermodynamic process comprising the successive steps of expanding an ignited charge, storing the energy thereby given out by the charge, forming a fresh charge with air in excess, compressing said charge by means of the stored energy, after partial compression withdrawing the excess air,

completing compression of the remainder, injecting fuel and repeating the cycle, and utilizing the withdrawn excess air.

2. A thermodynamic process comprising the successive steps of expanding an ignited charge, storing the energy thereby given out by the charge, forming a fresh charge with air in excess, compressing said charge by means of the stored energy, after partialcompression withdrawing the excess air, completing compression of the remainder, injecting fuel and repeating the cycle, and utilizing the withdrawn excess air in an expansion engine of the steam type.

3. A thermodynamic process comprising the successive steps of expanding an ignited charge ofair and fuel against a medium offering a constant opposed pressure and thereby storing the energy giyen out by the charge, forming afresh air charge with an excess of air proportional to the energy given out by the expanding charge, compressing said air charge by means of the stored energy, upon the air charge reaching a predetermined pressure withdrawing the excess air from the charge, completing the compression of the remaining air, injecting fuel and repeating the cycle, and utilizing the withdrawn excess air.

4. A two-stroke internal combustion en ergy transformer comprising a cylinder, a piston reciprocable therein and free to make outward expansion stroke of indefinite length and inward compression strokes, means applying fluid pressure continuously to the piston to resist and stop its outward strokeand to eifect its inward stroke, means to inject fuel behind the piston to effect its outward stroke, a valve for exhausting the gas used in the expansion stroke, a scavenging device for admitting fresh air behind the piston, and means to discharge a portion of the air charge during the inward stroke.

5. A two-stroke internal combustion energy transformer comprising a cylinder, a

.piston, means operating after partial compression of the air charge to discharge a portion of said air charge from the cylinder, and means operating upon the remaining air charge attaining a predetermined volume, to stop the discharge of air.

6. A two-stroke internal combustion energy transformer comprising a cylinder, :1. piston reciprocable therein and free to make outward expansion strokes of indefinite length and inward compression strokes, means applying fluid pressure continuously to the piston whereby its outward stroke is resisted and stopped and its inward stroke is effected, means to inject fuel to an air charge behind the piston to cause the expansion stroke, a valve for exhausting the expanded charge, a scavenging device for admitting a charge of fresh air behind the piston, an air outlet from the cylinder, a loaded valve governing the discharge of air through said outlet according to the pressure in the cylinder,and means actuated by movement of the piston for closing said outlet.

7. A two-stroke internal combustion cncrgy transformer comprising a cylinder, a piston reciprocable therein and free to make outward expansion stroke of indefinite length and inward compression strokes, means applying fluid pressure continuously to'the piston whereby its outward stroke is resisted and stopped and its inward stroke is effected, means to inject fuel to an air charge behind the piston to cause the expansion stroke,a valve for exhausting the expanded charge, a scavenging device for admitting a charge of fresh air behind the piston, an air outlet from the cylinder, a loaded valve governing the discharge of air through said outlet according to the pressure in the cylinder, and means actuated by movement of the piston for closing and unclosing said outlet and including a lost mo tion device whereby unclosing occurs during the outward stroke of the piston at a different piston position from the closing during the ,inward stroke.

8; A two-stroke internal combustion energy transformer comprising a cylinder, a piston, reciprocable therein and tree to make outward expansion strokes of indelinite length and inward compression strokes. means applying substantially constant fluid pressure continuously to the piston whereby its outward stroke is resisted and stopped and its inward stroke is effected means to inject fuel to an air charge behind the piston to cause the expansion stroke, a valve for exhausting the expanded charge, a scavenging devicerfor admitting a charge of fresh air behind the piston, an air outlet from the cylinder, a loaded valve governing the discharge of air through said outlet, and

means for closing said outlet before the termination of the inward stroke of the piston.

9. A two-stroke'internal combustion energy transformer comprising a cylinder a piston reciprocable therein and free to make outward expansion strokes of indefinite length and inward compression strokes.

.means applying fluid pressure continuously to the piston whereby its outward stroke is resisted and stopped and its inward stroke means to discharge a portion of the fresh' air charge during the inward stroke of the piston.

, 10. A two-stroke internal combustion en-- ergy transformer comprising a cylinder; a piston reciprocable therein and free to make outward expansion strokes of indefinite length and inward compression strokes,

means applying. fluid pressure continuously to the piston to resist and stop its outward stroke and to effect its inward stroke, means to inject fuel behind the piston to effect its outward stroke, a valve for exhausting the gas used in the expansion stroke, a scavenging device for admitting fresh air behind the piston, means to discharge a portion of the air charge during the inward stroke, a receiver for air under pressure, a connection therefrom to the cylinder, andvalve mechanism whereby air may be admitted from the receiver to the cylinder to drive the piston outwards.

11. A two-stroke internal ,combustion energy transformer comprising a cylinder, a piston reciprocable therein and free to make outward expansion strokes of indefinite length and inward compression strokes, means applying fluid pressure continuously to the piston to resistand stop its outward stroke and to efiect its inward stroke, means to inject fuel behind the piston to effect its outward stroke, a valve for exhausting the gas used in the expansion stroke, a scavenging device for admitting fresh air behind the piston, means to discharge a portion of the air charge during the inward stroke, a

receiver in which said air is stored under pressure, a connection from saidreceiver to the cylinder, a normally closed valve controlling said connection, valve actuating means reciprocating with the piston and tending to open said valve during the earlier part of the outward stroke of the piston and further means responsive to pressure in the cylinder for rendering said valve actuating means operative or not.

12. A two-stroke internal combustion energy transformer comprising a cylinder, a piston reciprocable therein and free to make outward expansion strokes of indefinite "length and inward compression strokes,

means applying fluid pressure continuously to the piston to resist and stop its outward stroke and to effect its inward stroke, means to inject fuel behind the piston to effect its outward stroke, a valve for exhausting trolling said connection, said valve exposing one face to the interior of the cylinder and having a piston on its stem, the inner faces of the valve and the contiguous face of the piston being exposed to the receiver pressure, and means to convey pressure fluid from the cylinder to act on the other face of the. valve piston. v

13. A two-stroke internal combustion en ergy transformer comprising a cylinder, a piston reciprocable therein and free to make outward "expansion strokes of indefinite length and inward compression strokes, means applying fluid pressure continuously to the piston whereby its outward stroke is resisted and stopped and its inward stroke is efiected, means to'inject fuel to an air charge behind the piston and rendered operative by cessation of 'the inward movement of the piston, a valve for exhausting the gas used in the expansion stroke, a scavenging device for admitting fresh air behind the piston, and-means to discharge a portion of the air charge during the inward stroke.

14. A two-stroke internal combustion energy transformer comprising a cylinder, a piston reciprocable therein and free to make outward expansion strokes of indefinite length and inward compression strokes,

tappet loosely attached to said member andmovable by its own momentum to trip the latch mechanism and thereby release the fuel pump, a valve for exhausting the gas used in the expansion stroke, a scavenging device for admitting fresh air behind the piston, and means to dischargea portion of the air charge during the inward stroke. 1

15. A two-stroke internal. combustion energy transformer comprising a cylinder, a pair of free pistons arranged to reciprocate oppositely therein means for applying fluid pressure continuously to the outer faces of the piston to resist their outward movement and to effect their inward movement, means whereby motive gas is expanded between the pistons to drive them outwardly, means whereby air is compressed and discharged by the reciprocation of the pistons, and means for ensuring symmetrical displacement of the pistons comprising a governor piston providing two similarly directed piston faces, means providing a column of liquid between each such face of the governor piston and a correspondingone of the outer faces of the transformer pistons, and means resisting outward movement of the governor piston due to outward movement of the transformer pistons.

16. A two-stroke internal combustion energy transformer con'iprising a cylinder, a pair of free pistons arranged to reciprocate oppositely therein, a governor piston providing a large piston face andtwo smaller faces similarly directed, means providing a liquid column between each of the smaller governor piston faces and a fraction of a corresponding one -of the outer faces of the transformer pistons, means applying fluid pressure to the remaining areas of the outer faces of the transformer piston and to the larger face of the governor piston, means whereby motive gas is expanded between'the transforn'ier pistons to drive them outwardly, and means whereby air is compressed and discharged by, the reciprocation of the transformer pistons.

17. A two-stroke internal combustion energy transformer comprising a cylinder, a pair of free pistons arranged to reciprocate oppositely therein, a governor piston providing a large piston face and two smaller faces similarly directed, means providing aliquid column between each of the smaller governor. piston faces and a fraction of a corresponding one of the outer faces of the transformer pistons, means rendered operative by unsymmetrical displacement of the t ans former pistons for selectively replenishing the liquid columns, means applying fluid pressure to the remaining areas of the outer faces of the transformer, piston and to the larger face of the governor piston, means whereby motive gas is expanded between the transformer pistons to drive them outwardly, and means whereby air is compressed and discharged by the reciprocation of the transformer pistons.

18. A two-stroke I internal combustion energy transformer comprising a cylinder, :1. pair of free pistons arranged to reciprocate oppositely therein, a governor piston providing a large piston face and two smaller faces similarlydirected, means providing a liquid column between each of the smaller governor pistonfaces and a fraction of a corresponding one of the outer faces of the transformer pistons, an epicyclic gear twoof whose rotative elements are connected to move positively with the transformer pistons and the third element of which is displaced proportionally to any difference of displacement of the transformer pistons, means operated b the third member, to control feeding of liquid to one 1i uid column or the other according to its irection 'of displacement, means applying fluid pressure to the remaining areas of the outer faces of the transformer piston and to the larger face of the governor piston, means whereby motive gas is expanded between the transformer pistons to drive them outwardly. and means whereby air is compressed and discharged by the reciproation of the transformer pistons.

1!). A two-stroke internal combustion energy transformer comprising a cylinder, a pair of free pistons arranged to reciprocate oppositely therein, means for applying fluid pressure continuously to the outer faces of the pistons, to resist their outward movement and to cll'cct their inward movements, means whereby motive gas is expanded between the pistons to drive them outwardly, means whereby air is compressed and discharged by the reciprocation of the pistons, and means external of the transformer cylinder for indicating the algebraic sum of the dispiaren'icuts of the pistons relatively to a fixed point of the cylinder.

20. A two-stroke internal combustion energy transformer comprising a cylinder, a pair of free pistons arranged to reciprocate oppositely therein, means for applying fluid pressure continuously to the outer faces of the pistons to resist their outward movements and to effect their inward movements, means whereby motive gas is'expanded hetwcen the pistons to drive them outwardly, means whereby air is compressed and discharged by the reciprocation of the pistons. and motion additive mea'ns actuated by the pistons jointly.

21. A two-stroke internal combustion energy transformer comprising a cylinder, a piston reciprocable therein and free to make outward expansion strokes of indefinite length and inward compression strokes, means applying fluid pressure continuously to the piston to resist and stop its outward stroke and to eil'ect its inward stroke, means to inject fuel behind the. piston to ellcct its outward stroke, a valve for exhausting the gas used in the expansion stroke, a scarenging device fo admitting fresh air behind the piston, means to discharge a portion of the air charge during the inward stroke, a receiver into which such air is discharged, an outlet from the receiver, and a valve controlled by the pressure in the receiver and controlling said outlet.

22. A two-stroke internal combustion energy transformer comprisinga cylinder, a piston reciprocable therein and free to make outward expansion strokes of indefinite length and inward compression strokes, means applying fluid pressure continuously to the piston to resist and stop its outward stroke and to effect its inward stroke, means to inject fuel behind the piston to effect its outward stroke, a valve for exhausting the gas used in the expansion stroke, a scavenging device for admitting fresh air behind the piston, means air charge during theinward stroke, a receiver into which such air is discharged, an outlet from the receiver, a valve controlled by thepressure in the receiver and controlling said outlet, and means controlled bythe pressurein the. receiver and controlling the fuel injection means.

, 23. A two-stroke internal combustion en; ergy transformer comprising a cylinder, a piston reoiprocable therein and free to make outward expansion strokes of indefinite length, and inward compression strokes, means applying fluid pressure continuously to the piston to resist and stop its outward stroke and means to inject fuel behind the piston .to efiect its outward stroke, a valve for to discharge a portion of theto eifeot its inward -stroke,'

exhausting the gas used in the expansion stroke, a scavenging device for admitting fresh air behind the piston, means to discharge a portion of the air charge during the inward compression ceiver for such disehargedair a connection therefrom to thecylinder, valve mechanism controlled jointly by the piston position and by the pressure in the cylinder whereby air may be admitted from the receiver to the cylinder to drive the piston outwards, an outlet from the receiver, avalve controlled by the pressure in the receiver and controlling said outlet, and means controlled by the pres sure in the receiver and controlling the fuel injection means.

In testimony whereof Iaflix my signature.

'WILHELM MAUSS.

stroke, a re 

